Customized module lid

ABSTRACT

A method of forming a custom module lid. The method may include placing a multichip module (MCM) between a module base and a temporary lid, target components are exposed through viewing windows in the temporary lid, a top surface of the target components is measured and mapped to create a target profile, the target profile is used to form custom pockets in a custom lid, and the custom pockets correspond to the target components.

This invention was made with United States Government support underDARPA Agreement No. H98230-13-D-0122. THE GOVERNMENT HAS CERTAIN RIGHTSIN THIS INVENTION.

BACKGROUND

The present invention generally relates to packaging of computer chipmodules, and more particularly to a custom module lid.

As microelectronics technology progresses, computer chip power densityis increasing. Devices that use computer chips are, in turn, becomingmore fully integrated and packaged closer together. Today small gaptechnology (SGT) and very thin thermal interface materials (TIM) areused to fill the gap between chips and module lids.

The SGT process works by placing shims on the chips and soldering copperpucks, centered over each chip, to the module lid. Once the pucks aresoldered in place the module lid top surface is machined flat so asecond thermal interface material can be added to the top surface andthen a heat sink or cold plate is installed.

SUMMARY

According to one embodiment of the present invention, a method isprovided. The method may include providing a module base, wherein themodule base includes a base pocket, the base pocket is an opening in themodule base on a top surface of the module base, and the base pocket hasa depth extending into the module base that is less than a thickness ofthe module base; placing a first thermal interface material (TIM) in thebase pocket, wherein the first TIM is on a bottom surface of the basepocket; placing a multichip module (MCM) on the module base, wherein theMCM includes a substrate, a first component, a second component and atarget component, the first component is a component on a bottom surfaceof the substrate, the second component and target component arecomponents on a top surface of the substrate, the first component has acorresponding base pocket and fits inside of the corresponding basepocket, the first TIM is between the bottom surface of the base pocketand a bottom surface of the first component, and the bottom surface ofthe substrate directly contacts a top surface of the module base;providing a temporary lid, wherein the temporary lid includes, a viewingwindow, a datum window and a temporary pocket, the viewing window andthe datum window are openings extending from a top surface of thetemporary lid to a bottom surface of the temporary lid, the temporarypocket is an opening in the temporary lid on the bottom surface of thetemporary lid, and the temporary pocket has a depth extending into thetemporary lid that is less than a thickness of the temporary lid;placing the temporary lid on the MCM, wherein the second component has acorresponding temporary pocket and fits inside of the correspondingtemporary pocket, the target component has a corresponding viewingwindow and fits inside of the corresponding viewing window, a portion ofthe substrate corresponds to the datum window, and the bottom surface ofthe temporary lid directly contacts the top surface of the substrate;measuring a surface profile of the target component through the viewingwindow and a surface profile of the substrate through the datum window;providing a custom lid, wherein the custom lid has a custom pocket and astandard pocket, the custom pocket and the standard pocket are openingsin the custom lid on a bottom surface of the custom lid, the custompocket and the standard pocket each have a depth extending into thecustom lid that are less than a thickness of the custom lid, the custompocket has an inside surface with a same profile as the target componentsurface profile, and the standard pocket has an inside surface with aflat profile; placing a second TIM in the custom pocket and in thestandard pocket, wherein a portion of the second TIM is on a top surfaceof the custom pocket and a portion of the second TIM is on a top surfaceof the standard pocket; and placing the custom lid on the MCM, whereinthe second component has a corresponding standard pocket and fits insideof the corresponding standard pocket, the target component has acorresponding custom pocket and fits inside of the corresponding custompocket, the second TIM is between the top surface of the custom pocketand the top surface of the target component, the second TIM is betweenthe top surface of the standard pocket and a top surface of the secondcomponent, and the bottom surface of the custom lid directly contactsthe top surface of the substrate.

According to another embodiment of the present invention, a method isprovided. The method may include placing a multichip module (MCM) on amodule base, wherein the MCM includes a substrate and a targetcomponent, the target component is on a top surface of the substrate,and a bottom surface of the substrate is in direct contact with a topsurface of the module base; providing a temporary lid including aviewing window, wherein the viewing window is an opening extending froma top surface of the temporary lid to a bottom surface of the temporarylid; placing the temporary lid on the MCM, wherein the target componentfits inside of the viewing window, and the bottom surface of thetemporary lid is on the top surface of the substrate; mapping a surfaceprofile of the target component through the viewing window; andproviding a custom lid having a custom pocket, wherein the custom pocketis an opening in the custom lid on a bottom surface of the custom lid,the custom pocket has a depth extending into the custom lid that is lessthan a thickness of the custom lid, and the custom pocket has an insidesurface with a same profile as the target component surface profile.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description, given by way of example and notintended to limit the invention solely thereto, will best be appreciatedin conjunction with the accompanying drawings, in which:

FIG. 1 is a top view of a multichip module, according to an exemplaryembodiment.

FIG. 2 is a cross section view of the multichip module, according to anexemplary embodiment.

FIG. 3 is a top isometric view of the multichip module, according to anexemplary embodiment.

FIG. 4 is a cross section view of the multichip module, according to anexemplary embodiment.

FIG. 5 is a bottom view of the multichip module, according to anexemplary embodiment.

FIG. 6 is a bottom isometric view of the multichip module, according toan exemplary embodiment.

FIG. 7 is an illustration of a module base, according to an exemplaryembodiment.

FIG. 8 is an exploded view of a first thermal interface material setbetween the multichip module and the module base, according to anexemplary embodiment.

FIG. 9 is an isometric view of the first thermal interface material setbetween the multichip module and the module base, according to anexemplary embodiment.

FIG. 10 is a cross section view of the module base, the first thermalinterface material and the multichip module, according to an exemplaryembodiment.

FIG. 11 is an exploded view of the module base, the multichip module anda temporary lid, according to an exemplary embodiment.

FIG. 12 is an isometric view of the module base, the multichip moduleand the temporary lid, according to an exemplary embodiment.

FIG. 13 is a top view of the multichip module and the temporary lid,according to an exemplary embodiment.

FIG. 14 is a cross section view of the module base, the temporary lidand the multichip module, according to an exemplary embodiment.

FIG. 15 is an exploded view of a second thermal interface material setbetween the multichip module and a custom module lid, according to anexemplary embodiment.

FIG. 16 is a cross section view of the module base, the first thermalinterface material, the second thermal interface material, the multichipmodule and the custom module lid, according to an exemplary embodiment.

FIG. 17 is an alternative exploded view of the second thermal interfacematerial set between the multichip module and a custom insert lid,according to an alternative embodiment.

FIG. 18 is an alternative cross section view of the module base, thefirst thermal interface material, the second thermal interface material,the multichip module and the custom insert lid, according to analternative embodiment.

The drawings are not necessarily to scale. The drawings are merelyschematic representations, not intended to portray specific parametersof the invention. The drawings are intended to depict only typicalembodiments of the invention. In the drawings, like numbering representslike elements.

DETAILED DESCRIPTION

Detailed embodiments of the claimed structures and methods are disclosedherein; however, it can be understood that the disclosed embodiments aremerely illustrative of the claimed structures and methods that may beembodied in various forms. This invention may, however, be embodied inmany different forms and should not be construed as limited to theexemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this disclosure will be thorough andcomplete and will fully convey the scope of this invention to thoseskilled in the art. In the description, details of well-known featuresand techniques may be omitted to avoid unnecessarily obscuring thepresented embodiments.

References in the specification to “one embodiment”, “an embodiment”,“an example embodiment”, etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

For purposes of the description hereinafter, the terms “upper”, “lower”,“right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, andderivatives thereof shall relate to the disclosed structures andmethods, as oriented in the drawing figures. The terms “overlying”,“atop”, “on top”, “positioned on” or “positioned atop” mean that a firstelement, such as a first structure, is present on a second element, suchas a second structure, wherein intervening elements, such as aninterface structure may be present between the first element and thesecond element. The term “direct contact” means that a first element,such as a first structure, and a second element, such as a secondstructure, are connected without any intermediary conducting, insulatingor semiconductor layers at the interface of the two elements. It shouldbe noted, the term “correspond” or “corresponding” may be a reference toa similar location and similar dimensions.

In the interest of not obscuring the presentation of embodiments of thepresent invention, in the following detailed description, someprocessing steps or operations that are known in the art may have beencombined together for presentation and for illustration purposes and insome instances may have not been described in detail. In otherinstances, some processing steps or operations that are known in the artmay not be described at all. It should be understood that the followingdescription is rather focused on the distinctive features or elements ofvarious embodiments of the present invention.

The present invention generally relates to packaging of computer chipmodules, and more particularly to a custom module lid. Ideally, it maybe desirable to form a module lid having customized pockets forcomponents with varying surface topography. One purpose of forming acustom module lid is to prevent undesirable or unavoidable gaps betweena chip component and a module lid.

One way to form a custom module lid is to set a multichip module on aprefabricated module base, then attaching a temporary lid to the modulebase leaving a top surface of a target component exposed through aviewing window, an optical or mechanical measurement technique may beused to measure and map the top surface of the target component, andforming a custom lid having a custom pocket with a same surface profileas the top surface of the target component. One embodiment by which toform a custom module lid is described in detail below with reference tothe accompanying drawings FIGS. 1-16.

Now referring to FIGS. 1-6, a multichip module (MCM) 50 during anintermediate step of a method of fabricating a custom module lid isillustrated, according to an embodiment. More specifically, the MCM 50may include multiple components (e.g., integrated circuit chips or“chips”) on a top and on a bottom of the MCM 50. FIG. 1 illustrates atop view of the MCM 50 along an x-z plane, FIG. 2 illustrates a crosssection view of the MCM 50 taken along section line A, FIG. 3illustrates an isometric view of the MCM 50, FIG. 4 illustrates thecross section view of the MCM 50 taken along section line B, FIG. 5illustrates a bottom view of the MCM 50 along an x-z plane, and FIG. 6illustrates an isometric view of the MCM 50. It should be noted, forillustrative purposes, the cross section views of the MCM 50 mayillustrate a top surface of the integrated circuit chips along sectionline A and a bottom surface of the integrated circuit chips alongsection line B, for illustrative purposes. Also, the integrated circuitchips may be referred to as chips or components.

The MCM 50 may include multiple components on a substrate 101. Thesubstrate 101 may be an organic or inorganic substrate. In anembodiment, the substrate 101 may be an organic laminate or ceramic. Thesubstrate 101 may have a module thickness (MT) of about 0.7 mm, a modulewidth (MW) of about 90 mm, and a module length (ML) of about 170 mm, butother dimensions may be used. The substrate 101 may have connectionfeatures formed thereon (not illustrated), which may be operativelyinterconnected with connection points of the components (e.g., signaltraces or tracks formed on the top and/or bottom surfaces using aconductive material such as copper, with contact pins, tines, sockets,pads or strips at terminal ends of the traces).

The components may be adhesively bonded or mechanically fastened to thesubstrate 101, and electrical connections may be completed using varioustechnologies, such as, for example, solder balls (e.g., controlledcollapse chip connection, or “C4”) or surface mount technology.Alternatively, the components can be deposited on the substrate 101using thin film technology.

The components may include, for example, a hybrid memory cube (HMC) 116,an application-specific integrated circuit (ASIC) 118, a dynamicrandom-access memory (DRAM) 110, a trusted platform module (TPM) 114, aconnector 120, a soft switch 121, a baseboard management controller(BMC) 122, a switch 126, a voltage transformation module (VTM) 124, a3.3V buck regulator 125, a 1.5V buck regulator 127, a region 112, aregion 123, and/or other module components. A region 112 may include,for example, an ARM processor, a crystal 24 MHz, an LDO, and flashmemory. A region 123 may include, for example, a BMC oscillator, a BMCuReset, an RS485, a fan-out buffer, a crystal 25 MHz, and a serialelectrically-erasable programmable read-only memory (SEEPROM). TheASIC(s) 118 (which may act as processors) and the HMC(s) 116 may havethe highest power dissipation densities among all of the chips on theMCM 50, so they may be placed on the top surface of the substrate 101for subsequent measurements.

In an embodiment, a first component may be on a bottom surface of thesubstrate 101, a second component and a target component may be on a topsurface of the substrate 101. The target component may include acomponent having higher surface peak fluctuations (e.g., components thatmay pose a problem if packaged in a pocket having a flat inside pocketsurface). The first component may include the connector 120, the softswitch 121, the BMC 122, the switch 126, the VTM 124, the 3.3V buckregulator 125, the 1.5V buck regulator 127, and/or the region 123. Thesecond component may include the HMC 116, the DRAM 110, the TPM 114, andthe region 112. The target component may be the ASIC 118. It should benoted, any number of chips may be located on the top surface and/or thebottom surface of the MCM 50.

Now referring to FIG. 7, an apparatus 100 during an intermediate step ofa method of fabricating a custom module lid is illustrated, according toan embodiment. More specifically, the method may include fabricating amodule base 149.

The module base 149 may be formed using any known formation techniquesknown in the art, such as, for example, a machine processing technique.The module base 149 may include any durable material having a highthermal conductivity, such as, for example, a metal or metallic alloyincluding aluminum. The module base 149 may have a base thickness (BT)of about 14.5 mm, a base width (BW) of about 102 mm, and a base length(BL) of about 182 mm, but other dimensions may be used. The dimensionsof the module base 149 may vary depending on MCM 50. In an embodiment,the base width (BW) is larger than the module width (MW) and the baselength (BL) is larger than the module length (ML).

The module base 149 may include a base pocket 148. The base pocket 148may be formed in the module base 149 using any method known in the art,such as, for example, a machine processing technique. The module base149 may be an opening in the module base 149 extending from the topsurface of the module base 149. The base pocket 148 may have a depthbeing less than the base thickness (BT). A top surface of the modulebase 149 may be machined to form a flat surface, preferably within±0.0005 in.

In an embodiment, there are multiple base pockets 148, where each basepocket 148 has corresponding dimensions and x-z plane location as acorresponding first component (e.g., components on a bottom surface ofthe substrate 101, described above), such that the first component mayfit inside of the corresponding base pocket 148. In the embodiment, fourmodule bases 149 are illustrated and each module base 149 is fastened toa jig plate 145. It should be noted, the term “correspond” or“corresponding” may be a reference to similar locations and/or similardimensions.

In an alternative embodiment (not illustrated), the module base may havea slot extending around a perimeter of the module base 149. The slot mayprovide a connection for subsequent module lid attachment. The topsurface of the module base 149 may be recessed below the slot or asidewall, such that a portion of, or an entirety of, the MCM 50 may fitwithin the recess.

Now referring to FIGS. 8-10, an apparatus 100 during an intermediatestep of a method of fabricating a custom module lid is illustrated,according to an embodiment. More specifically, the method may includeplacing the MCM 50 on the module base 149. FIG. 10 may include a crosssection view of the MCM 50 and the module base 149. Additionally, FIG.10 includes a section view taken along section C.

A first thermal interface material (TIM) 161 may be inserted in the basepocket 148. The first TIM 161 may include any thermal interface materialknown in the art, such as, for example, an elastomeric thermal interfacematerial. However, it may be advantageous to use a more efficientthermal material over components having high power densities (e.g., thetarget components), such as, for example, a curable thermal gel. Thefirst TIM 161 may have a thickness from about 0.5 mm to about 0.75 mm,but other thicknesses may be used.

The MCM 50 may be placed on the module base 149. The first component mayfit into a corresponding base pocket 148. The first TIM 161 may bebetween the first component and a bottom surface of the base pocket 148.There may be a clearance gap (d1) between the first component and asidewall of the base pocket 148 ranging from about 1 mm to about 2 mm. Atop portion of the module base 149 that is in-between the base pockets148 and/or within a perimeter of the module base 149 may be referred toas a base support rib 146. The bottom surface of the substrate 101 maybe directly on the base support rib 146 (i.e., the bottom surface of thesubstrate 101 is coplanar with a top surface of the base support rib146).

Now referring to FIGS. 11-14, the apparatus 100 during an intermediatestep of a method of fabricating a custom module lid is illustrated,according to an embodiment. More specifically, the method may includeplacing a temporary lid 139 on the module base 149 to measure targetcomponent topography. FIG. 14 may include a cross section view of thetemporary lid 139, the MCM 50 and the module base 149, taken alongsection line AA. Additionally, FIG. 14 includes a section view takenalong section D.

The temporary lid 139 may include a viewing window 138, a datum window132 and a temporary pocket. The viewing window 138 and the datum window132 may be openings in the temporary lid 139 and extend through thetemporary lid 139 (i.e., extending from a top surface of the temporarylid 139 to a bottom surface of the temporary lid 139). The viewingwindow 138 may have similar, but slightly larger, dimensions as thetarget component (e.g., the ASIC 118) in the x-z plane. The temporarypocket may be an opening on the bottom surface of the temporary lid 139that extends a distance into the temporary lid 139 equal to a distanceless than the thickness of the temporary lid 139. The temporary pocketmay have similar, but slightly larger, dimensions as the secondcomponent in the x-z plane (e.g., the HMC 116). A bottom portion of thetemporary lid 139 that is in-between the viewing window 138, the datumwindow 132, the temporary pocket and/or within a perimeter of thetemporary lid 139 may be referred to as a temporary support rib 136.

The temporary lid 139 may be placed on the MCM 50. The second componentmay fit inside of the temporary pocket and the target component may fitinside of the viewing window 138 (e.g., the second component may becovered by the temporary lid 139 and the target component may be exposedthrough the viewing window 138). A bottom surface of the temporarysupport rib 136 may be directly on the top surface of the substrate 101(i.e., the bottom surface of the temporary support rib 136 is coplanarwith the top surface of the substrate 101). The viewing window 138 maybe larger than the target components by a clearance gap (d2). Theclearance gap (d2) may range from about 1 mm to about 2 mm, but otherdistances may be present.

In an embodiment, there may be four target components (four ASIC's 118)and four corresponding viewing windows 138 where the four targetcomponents are inside of the four viewing windows 138. There may bemultiple second components that are inside of the temporary pockets.There may be three datum points that expose three different portions ofthe substrate 101. Also, the temporary lid 139 may be fastened to themodule base 149 using screws, brackets, slots, fins or any other means.The temporary lid 139 and the module base 149 may apply pressure to theMCM 50 through the base support rib 146 and the temporary support rib136. A temporary fin around the perimeter of the temporary lid 139 mayfit inside the slot of the module base 149 (not illustrated).

Once the temporary lid 139 is placed on the MCM 50, a reference planemay be measured through the datum window 132. The reference plane may bethe top surface of the substrate 101. Next, a top surface of the targetcomponent may be measured through the viewing window 138 for surfaceflatness, imperfections, altered dimensions, or other variations. Thetop surface of the target component may be measured in reference to thereference plane. The top surface of the target component and the topsurface of the substrate 101 may be measured using any measurementtechnique known in the art, such as an optical or mechanical process andmay be applied to a computer added drawing program for mapping (i.e.,create a target surface profile 133). After the target surface profile133 is measured and/or mapped, the temporary lid 139 may be removed. Inan alternative embodiment, the temporary lid 139 may remain on theapparatus 100 and inserts (described with reference to FIGS. 17 and 18)may be placed in the viewing windows 138 and/or in the datum window 132.The target surface profile 133 may be subsequently used to form a custompocket in a custom lid.

In an embodiment, the target component may include four ASIC's 118having high power densities compared to other heat dissipatingcomponents on the MCM 50. The four ASIC's 118 may have fourcorresponding viewing windows 138. A top surface of the ASIC's 118 maybe measured using an optical process and an ASIC profile may be createdon a computer aided program for subsequent ASIC pocket formation in acustom module lid.

Now referring to FIGS. 15 and 16, the apparatus 100 during anintermediate step of a method of fabricating a custom module lid isillustrated, according to an embodiment. More specifically, the methodmay include forming a custom lid 179 and placing the custom lid 179 onthe module base 149. FIG. 16 may include a cross section view of thecustom lid 179, the MCM 50 and the module base 149. Additionally, FIG.16 includes a section view taken along section E.

The custom lid 179 may be formed using any known formation techniquesknown in the art, such as, for example, a machining process. The customlid 179 may include any durable material having a high thermalconductivity, such as, for example, a metal or metallic alloy includingaluminum. The custom lid 179 may have similar dimensions as the modulebase 149, for example, having a lid thickness (LT) of about 14.5 mm, alid width (LW) of about 102 mm, and a lid length (LL) of about 182 mm,but other dimensions may be used. The dimensions of the custom lid 179may vary depending up the size of the MCM 50. In an alternativeembodiment, the custom lid 179 may have a nominal thickness of about 10mm. Additionally, the custom lid 179 may include a lid fin around theperimeter of the custom lid 179 and may fit inside the slot of themodule base 149 (not illustrated).

It should be noted, the custom lid 179 and the module base 149 may eachbe fabricated from a single piece of material but, alternatively, thecustom lid 179 and the module base 149 may be constructed from multipleblocks of different or similar materials and attached using conventionalmeans. In an embodiment, the custom lid 179 may be a cold plate or heatsink to create additional thermal support for the process or packaging.

A custom pocket 175 and a standard pocket may be formed in the customlid 179. The custom pocket 175 and the standard pocket may be formedusing any method known in the art, such as, for example, a machineprocessing technique. The custom pocket 175 may have similar, butslightly larger, dimensions as the target component (in the x-z plane).A custom surface 173 may be formed in the custom pocket 175 and may be atop surface of the custom pocket 175. The custom surface 173 may beformed from the dimensions and layout of the target surface profile 133.The standard pocket may have similar, but slightly larger, dimensions asthe second component (in the x-z plane). The standard pocket may have aflat inside surface, as is typically used during packaging.

A second TIM 151 may be inserted in the custom pocket 175 and in thestandard pockets. The second TIM 151 may improve the thermal interfacebetween the components and the custom surface 173 or the flat surface.The second TIM 151 may be any thermal interface material known in theart, such as, for example, a curable thermal gel. The second TIM 151 mayhave a thickness from about 0.025 mm to about 0.05 mm, but otherthicknesses may be used.

The custom lid 179 may be placed on the MCM 50. The second component mayfit inside of the standard pocket and the target component may fitinside of the custom pocket 175. A bottom portion of the custom lid 179that is in-between the standard pocket, the custom pocket 175 and/orwithin the perimeter of the custom lid 179 may be referred to as a lidsupport rib 176. A bottom surface of the lid support rib 176 may bedirectly on the top surface of the substrate 101 (i.e., the bottomsurface of the lid support rib 176 is coplanar with the top surface ofthe substrate 101). There may be a clearance gap (d3) between the targetcomponent and the custom pocket 175. The clearance gap (d3) may rangefrom about 1 mm to about 2 mm, but other distances may be present.

In an embodiment, the target component may include four ASIC's 118. Thefour ASIC's 118 may have four corresponding custom pockets 175. Theremay be four custom surfaces 173 that match the target surface profile133 of the corresponding ASIC 118.

Now referring to FIGS. 17 and 18, an alternative apparatus 200 during anintermediate step of a method of fabricating a custom module lid isillustrated, according to an alternative embodiment. More specifically,the method may include placing inserts 238 in the viewing window 138.FIG. 18 may include a cross section view of the temporary lid 139, theMCM 50 and the module base 149. Additionally, FIG. 18 includes a sectionview taken along section F. It should be noted, FIG. 17 is analternative embodiment of the apparatus 100 illustrated in FIG. 15 andFIG. 18 is an alternative embodiment of the apparatus 100 illustrated inFIG. 16.

A custom lid 279 may include the temporary lid 139 and inserts 238placed in the viewing window 138 and/or in the datum window 132 afterthe target surface 133 is measured. It should be noted, the custominsert lid 279 may be similar (e.g., similar dimensions) to the customlid 179 described with reference to FIGS. 15 and 16. The inserts mayhave a custom insert surface 233 as a bottom surface. The inserts 238may be formed using any known formation techniques known in the art,such as, for example, a machining process. The custom insert surface 233may be similar to the target surface 133. The inserts 238 may includeany durable material having a high thermal conductivity, such as, forexample, a metal or metallic alloy including aluminum. The inserts 238may have similar, but slightly smaller, dimensions as the viewing window138 and/or the datum windows 132. In the illustrated embodiment, fourinserts 238 are inserted into four viewing windows 138. Once the inserts238 are placed in the viewing window 138, a top surface of the inserts238 may be coplanar with the top surface of the temporary lid 139 andthe custom insert surface 233 may be a distance above the bottom surfaceof the temporary lid 139, such that a custom insert pocket 235 remainsbelow the inserts 238. The custom insert pocket 235 may have similar,but slightly larger, dimensions as the target component (in the x-zplane).

In an embodiment, the inserts 238 may be placed in the viewing windows138 after the target surface 133 is measured and while the temporary lid139 is on the MCM 50. In such an embodiment, the second TIM 151 may beinserted before the inserts 238 are placed in the viewing window 138. Inan alternative embodiment, the temporary lid 139 may be removed,followed by placing the inserts 238 into the viewing window 138, placingthe second TIM 151 in the custom insert pockets 235, then placing thecustom insert lid 279 on the MCM 50.

One of the benefits of this invention may include a solution to aproblem of creating a uniform gap between a package and modulecomponents. One of the exemplary embodiments of this invention includesmapping of a top surface of a multichip module (MCM) using eitheroptical or mechanical measurement techniques and then to custom machinea bottom surface of a lid to match the MCM profile. This may allow auniform gap between the chip surface and the MCM regardless of thecurvature of the chip. This invention may allow for more uniform TIMthickness on the top surface of the chip and the module lid. It shouldbe noted, a module package may have a different physical orientation(e.g., a vertically-disposed module substrate) but the invention maystill be applied to such arrangements.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.The terminology used herein was chosen to best explain the principles ofthe embodiment, the practical application or technical improvement overtechnologies found in the marketplace, or to enable others of ordinaryskill in the art to understand the embodiments disclosed herein.

What is claimed is:
 1. A method comprising: placing a multichip module(MCM) on a module base, wherein the MCM includes a substrate and atarget component, the target component is on a top surface of thesubstrate, and a bottom surface of the substrate is in direct contactwith a top surface of the module base; providing a temporary lidincluding a viewing window, wherein the viewing window is an openingextending from a top surface of the temporary lid to a bottom surface ofthe temporary lid; placing the temporary lid on the MCM, wherein thetarget component fits inside of the viewing window, and the bottomsurface of the temporary lid is on the top surface of the substrate;mapping a surface profile of the target component through the viewingwindow; and providing a custom lid having a custom pocket, wherein thecustom pocket is an opening in the custom lid on a bottom surface of thecustom lid, the custom pocket has a depth extending into the custom lidthat is less than a thickness of the custom lid, and the custom pockethas an inside surface with a same profile as the target componentsurface profile.
 2. The method of claim 1, wherein the target componentincludes an application-specific integrated circuits.
 3. The method ofclaim 1, wherein the target component is measured using an opticalprocess.
 4. The method of claim 1, wherein the custom lid is a coldplate.
 5. The method of claim 1, wherein the module base includes a slotand the custom lid includes a corresponding fin, and the correspondingfin fits inside of the slot.
 6. The method of claim 1, wherein thesubstrate is an organic laminate.
 7. The method of claim 1, wherein themodule base and the custom lid are aluminum.
 8. A method comprising:placing a multichip module (MCM) on a module base, wherein the MCMincludes a substrate and a target component, the target component is ona top surface of the substrate, and a bottom surface of the substrate isin direct contact with a top surface of the module base; providing atemporary lid including a viewing window, wherein the viewing window isan opening extending from a top surface of the temporary lid to a bottomsurface of the temporary lid; placing the temporary lid on the MCM,wherein the target component fits inside of the viewing window, and thebottom surface of the temporary lid is on the top surface of thesubstrate; mapping a surface profile of the target component through theviewing window; and providing a custom lid having a custom pocket,wherein the custom pocket is an opening on a bottom surface of thecustom lid, and the custom pocket has an inside surface with a sameprofile as the target component surface profile.
 9. The method of claim8, wherein the target component includes an application-specificintegrated circuits.
 10. The method of claim 8, wherein the targetcomponent is measured using an optical process.
 11. The method of claim8, wherein the custom lid is a cold plate.
 12. The method of claim 8,wherein the module base includes a slot and the custom lid includes acorresponding fin, and the corresponding fin fits inside of the slot.13. The method of claim 8, wherein the substrate is an organic laminate.14. The method of claim 8, wherein the module base and the custom lidare aluminum.
 15. A method comprising: placing a multichip module (MCM)on a module base, wherein the MCM includes an organic substrate and atarget component, the target component is on a top surface of theorganic substrate, and a bottom surface of the organic substrate is indirect contact with a top surface of the module base; placing atemporary lid on the MCM, wherein the temporary lid includes an openingextending through an entire thickness of the temporary lid, wherein thetarget component fits inside of the opening, and a bottom surface of thetemporary lid directly contacts the top surface of the organicsubstrate; mapping a surface profile of the target component through theopening; and providing a custom lid having a custom pocket, wherein thecustom pocket in a bottom surface of the custom lid, and the custompocket has an inside surface with a same profile as the target componentsurface profile.
 16. The method of claim 15, wherein the targetcomponent includes an application-specific integrated circuits.
 17. Themethod of claim 15, wherein the target component is measured using anoptical process.
 18. The method of claim 15, wherein the custom lid is acold plate.
 19. The method of claim 15, wherein the module base includesa slot and the custom lid includes a corresponding fin, and thecorresponding fin fits inside of the slot.
 20. The method of claim 15,wherein the module base and the custom lid are aluminum.